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When I was younger I saw a movie of relatively grainy quality. I think the movie was centered around a young brother and sister duo, but I don't know what they were trying to accomplish. towards the end though the protagonists meet a female alien in a sort of dark room, I think the room contained a variety of technologies and among those was a TV. The Female alien had big lips and eyes that stuck up over her head like antennae. The alien had sort of a "Marilyn Monroe" essence about her. I've been trying to find this movie for quite some time now so if you can, please help me out.